Question 173480
The way to look at this in EVERY situation is that you never subtract.  You always add the additive inverse.  For any number {{{a}}}, the additive inverse is {{{-a}}}.  Just remember that if {{{a<0}}} then {{{-a>0}}}.


So, if you have (-16) on one side and you want to get rid of it, add the additive inverse of (-16), namely 16.


So:


{{{y+(-16)=-12}}}


{{{y+(-16)+(16)=-12+16}}}


{{{y+0=4}}}


{{{y=4}}}


Similarly, you also NEVER divide.  You always multiply by the multiplicative inverse.  If {{{a}}} is any number other than zero, then the multiplicative inverse is {{{1/a}}}.  So if you had {{{2x=4}}}, you would multiply both sides by {{{1/2}}} which is the multiplicative inverse of the {{{2}}} coefficient on the variable.